NBC's Brian Williams and Pete Williams discuss the steps law enforcement officials are taking to discover if the bombing suspects had any accomplices.

Security

DOJ Anounces Arrest of Alleged New York State ISIS Recruiter

Jeh Johnson on Using Personal Email on Work Computer: Whoops not a Good Practice

NBC News
July 21, 2015

Netanyahu to Holt: Iran Deal Poses Great Danger to Israel, America and the World

NBC News
July 15, 2015

Clapper Calls China 'Leading Suspect' in OPM Hack

NBC News
June 25, 2015

Former FBI Agent: Supremacist Groups Always Looking for New Recruits

NBC News
June 23, 2015

Flashback: Edward Snowden Revealed as NSA Whistleblower

June 09, 2015

Authorities Release Video of Rahim Shooting

NBC News
June 08, 2015

Combating Viral Terrorism

NBC News Channel
June 04, 2015

Police: Arrest Made in Boston Terror Plot

NBC News Channel
June 03, 2015

Gyro Pilot: 'We Can Return Our Democracy to the People'

NBC News
May 21, 2015

Arrests Made in German Right Wing Extremist Plot

NBC News
May 06, 2015

FAA: Approach to Drones 'Test a Little, Learn a Little, Try a Little'

NBC News
May 06, 2015

This content comes from Closed Captioning that was broadcast along with this program.

>>as promised to d.c. we go and
pete williams
who has not had a lick of rest since this next round started. again, pete, when you look at the calendar,
5:30 p.m
. eastern we get the imagery. we both knew at the time the web has a funny way of taking off on its own. this was
crowd sourcing
and investigation by the
fbi
really first of its kind getting the imagery out, letting everybody look at it, sink in, and then we were off on these various and violent tangents that lacked a specific tie. i think it was close to
4:00 a.m
. when you came on the air and said we now have kind of every reason. to believe these are tied together.

>>yes, and let's go back to last night too. everything about this is extraordinary. the response by the public to the
fbi
's website was the largest single volume of visits to the
fbi
's website ever. it set a record. nearly crashed the system. a huge volume of tips came in. and they were names that frankly a lot of them were wrong, of course, but some were right. and the
fbi
, i'm told, had already been sort of looking a at these two based on some investigation they had done on their own since the marathon bombing. so that led them looking at them but what touched this whole thing off, the spark that ignited all this was not any
police action
. it was the decision on these men to grab some cash and try to make a run for it in
someone else
's car in case the authorities might be looking for their car can they thought they would steal one. that ended up with a shootout. you were just talking to richard about the hail of gunfire. it's possible that the surviving brother was hit. i've talked to a couple
law enforcement
officials who say they found some blood in the area after he abandoned the car, which indicates, and there may be some in the car too, which indicates he may have been hit. his other brother was shot outside the car. he remained inside the car.

>>please continue.

>>so as for what's going on in boston, all throughout the day since the
early morning
hours, the
fbi
, the
boston police
, the authorities in massachusetts, the
state police
have been pursuing reports that they didn't act on their own and had accomplic accomplices. they look at these things and think they can knock it down and another one comes up. the best information i have right now is they have not, in all of this checking, uncovered any indication that there were more than two people involved in the marathon bombing. they are still looking at possibility that they might have had accomplices. they can't rule it out. that's what they are looking into. that's why we call it an investigation. but nothing that can be confirmed. but it's because of the possibility that that's one factor why you see the lockdown in boston and the real fact that a bomb was found this morning and disabled. a bomb that i'm told was similar in design to some of the explosi explosives that these two had as they were being followed by the police into watertown. let me just say one other thing about the kind of person who set this bomb in the
boston marathon
. while we saw some videotape during the
fbi
's news conference, we didn't see all pictures the
fbi
has. and the reason i'm told that they got so excited about the man on the left, the man with
white hat
that they are still trying to find, is that they see video of him setting off the bomb. if you think about that picture that we have shown many times from our affiliate that shows what thought might have been the bomb placed in a
trash bag
next to a mailbox on the street as people are running by, think of that picture in your mind and realize that that is where they believe the bomb was set. not next to the mailbox and where the
trash bag
was, but just behind the barrier that is crowded with people. what i'm told you see on the video is that this it man here that you're looking at there, walking by, goes up near the front and in the midst of the crowd with all these people around him, he takes his backpack off, that's where it goes off. that picture there. that's the after picture. just before that, there were people all standing there, several people deep. there's the picture. so you see this
black shadow
picture of the bag that might be the bomb. it it turns not to have been. it was placed right behind that crowd barrier where all those people are standing. moments before he was standing among them shoulder to shoulder. he removes his backpack and then they see him
walk away
and they hear the first bomb go off. he looks down and then he moves away rapidly. 13 seconds later the bomb goes off in the very place he had been standing shoulder to shoulder with all those people. that's the kind. of person the
fbi
believes he was.

>>and that's very motivating to all the people trying to find him. pete, i saw some imagery that i don't think i have seen on television. it was from
social media
last night. another civilian's
photo showing
him prior to release iing the backpack from his shoulder. you see martin richard at the barricade, his mother, his sister jayne, his dad. if you know what to look for, the gentleman we later saw who lost a leg, his life was being saved by the man in the
cowboy hat
. he was wearing a
yellow hat
crossing in front of suspect number two. you see life frozen in time while people are just having a good time and you see this guy who is about to do what we now know and believe he did. that's the incredible disconnect between. those of us who go on about our lives and follow the law and think normal thoughts and someone capable of carrying this out.

>>exactly. and then of course, the remarkable events of last night where they in essence walk up to a
campus police
officer and shoot him dead and continue on their way. the brother has bombs strapped to his chest. it's astonishing.

>>it really is.
pete williams
who has helped us piece our way through this investigation throughout. we have unfortunately we already know we have other